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Odd composite numbers n such that primitive part of Fibonacci(n) (see A061446) is prime.
7

%I #15 Jan 06 2020 08:34:59

%S 9,15,21,33,35,39,45,51,63,65,75,93,105,111,119,121,123,135,145,185,

%T 195,201,207,209,225,231,235,245,285,287,299,301,321,335,363,399,423,

%U 453,473,693,707,771,1047,1113,1215,1365,1371,1387,1533,1537

%N Odd composite numbers n such that primitive part of Fibonacci(n) (see A061446) is prime.

%H David Broadhurst, <a href="/A061254/b061254.txt">Table of n, a(n) for n=1..151 yielding primes or probable primes</a>

%H J. Brillhart, P. L. Montgomery and R. D. Silverman, <a href="https://doi.org/10.1090/S0025-5718-1988-0917832-6">Tables of Fibonacci and Lucas factorizations</a>, Math. Comp. 50 (1988), 251-260, S1-S15. Math. Rev. 89h:11002.

%t A061446[n_] := Product[Fibonacci[d]^MoebiusMu[n/d], {d, Divisors[n]}];

%t Select[Range[1, 1999, 2], CompositeQ[#] && PrimeQ[A061446[#]]&] (* _Jean-François Alcover_, Jul 04 2019 *)

%Y Cf. A061446, A061447, A061445, A061442, A061443.

%K nonn

%O 1,1

%A _David Broadhurst_, Jun 10 2001

%E Definition corrected by _T. D. Noe_, Dec 14 2006